Almost half of 346,000 deaths from 12 cancers among U.S. adults in one year are attributed to cigarette smoking, despite 50 years of progress on butting out, new research suggests.

Cancer researchers updated the estimate on deaths due to cigarette smoking to reflect changes in smoking patterns and how some data now suggest that the risk of cancer death among smokers can increase over time.

Of 345,962 cancer deaths in the U.S. in 2011, 167,805 or 48.5 per cent were attributed to smoking cigarettes, Rebecca Siegel and her co-authors said in a research letter published in Monday's issue of JAMA Internal Medicine.

The largest proportions of cancer deaths linked to smoking among those 35 and older were for cancers of the lung, bronchus and trachea (125,799 of 156, 855 deaths or 80 per cent) and larynx (2,856 of 3,728 deaths or nearly 77 per cent).

About half of the deaths from cancers of the oral cavity, esophagus and urinary bladder were also attributable to smoking.

Smoking was also cited as the cause of many deaths from cancer of the colon, kidney, liver, pancreas, stomach, cervix, and from myeloid leukemia.             

"Cigarette smoking continues to cause numerous deaths from multiple cancers despite half a century of decreasing prevalence," Rebecca Siegel from the American Cancer Society in Atlanta and her co-authors said.

Dr. Norman Edelman, a senior scientific advisor to the American Lung Association, said when people hear about smoking and cancer, their thoughts often turn to lung cancer alone.        

"This study shows that there is a huge burden of other cancers caused by smoking in addition to lung cancer," Edelman  said.

It will take 30 to 40 years to see the consequences of smoking among current smokers, Siegel said.

"Continued progress in reducing cancer mortality, as well as deaths from many other serious diseases, will require more comprehensive tobacco control, including targeted cessation support," her team concluded.

But smoking cessation support was less than ideal in a second paper published in the same issue.

In Canada and the U.S., family physicians and nurse practitioners are encouraged to reach out to smokers and encourage them to quit using the 5As: 

  • Ask about current smoking status.
  • Advise to stop smoking  and provide information on the benefits of quitting.
  • Assess willingness to quit.
  • Assist with finding resources and making a plan to quit, such as recommending nicotine replacement therapies and recommending counselling through quit lines.
  • Arrange follow-up to help the patient follow through, such as suggesting a visit or phone call.

Low assistance rates

Elyse Park of from Massachusetts General Hospital in Boston and her team asked continued smokers and quitters participating in a national lung screening trial about whether their doctor actively intervened. They said assistance was associated with a 40 per cent increase in the odds of quitting and arranging was associated with a 46 per cent increase.

"Only one in 10 smokers reported that their provider arranged follow-up for smoking cessation in the year after the initial screen; this is similar to previously reported low rates of arranging follow-up," Park and her team said.

"Our findings confirm the need for clinicians to take more active intervention steps in helping patients who undergo screening to quit smoking."

Likewise in 2012, six in 10 respondents over the age of 18 in Ontario who smoked (57 per  cent) and had visited a physician in the past year had been advised to quit smoking, according to the Ontario Tobacco Research Unit's 2014 report.

Dr. Michael Ong of the general internal medicine division at the University of California, Los Angeles wrote a journal editorial on the U.S. research, titled "Tobacco Cessation — We Can Do Better."

"The low rates of assisting and arranging for smoking cessation are particularly distressing because physicians and patients were provided the written results of the lung screening examination. High rates of effective action did not occur despite the teachable moment of opportunity of discussing the results of the lung screening," Ong said.

All health-care professionals need to work collaboratively to help people stop smoking, such as referring to telephone-based counselling, said Ong, who also acknowledged the time commitment. The Canadian Cancer Society's online and phone counselling services also include access to coaches to help smokers to create a customized quit plan.

Smoking prevalence in Canada was about 16 per cent or 4.6 million smokers, according to Health Canada's  2012 Canadian Tobacco Use Monitoring Survey

With files from HealthDay News